RepoData

In order to answer the question, "How many archives are vulnerable to climate change?" you have to know where archives are located. Up until 2017, the largest available and reusable (due to its location information) data set was the ArchiveGrid set of repositories, which numbered just over 1,200 repositories. The map below shows the ArchiveGrid repositories. This data set was the basis of a  2018 research article  I co-authored with colleagues from Penn State University, assessing the risks of various climate change factors to US archives.

But as we started digging into this data, it was clear that many smaller repositories were quite literally off the map. The OCLC ArchiveGrid data set is made up of institutions which have the resources to put EAD-encoded finding aids online. Where were the lower profile archives, or institutions that may not be traditionally thought of as an archive, but still had responsibility for archival records?

In 2017, my collaborator Ben Goldman and I received a grant from the Society of American Archivists Foundation to create a comprehensive data set of US archives. We hired a research assistant, Whitney Ray, and the RepoData project team set out to try to answer a seemingly simple question: How many archives exist in the United States? And where are they located?

The RepoData project team contacted over 150 archival organizations for any lists or directories they had with archives and institutions with archival records across the United States. This data was then reviewed extensively to distinguish between mailing addresses and physical locations, as well as sorting repositories into the following categories: Historical Society/Museum, Government, Public Library, College/University, Corporation, Religious, K-12, and Tribal.

After cleaning up the data, we had over 25,000 data points, and over 18,000 physical locations that we were able to geolocate on a map, as illustrated below:

By comparing the "before" data from OCLC ArchiveGrid (the orange dots) with the "after" data from RepoData (the gray dots), it becomes clear how many smaller archives were surfaced as a result of the RepoData project.

Because the organizations that sent us source data often had different methods for compiling their own data (for example, some had data from state historical records surveys, others had data solely from their membership lists), there were some states that were over- and under-represented in different categories. The slideshow below shows the major categories.

While all of the examples shown above depict the continental United States, the RepoData set includes data for Alaska and Hawaii. The different colored dots correspond with different types of repositories - see the slideshow above for details.

What would happen to archives in an extreme sea level rise scenario?  According to NOAA , 6 feet of sea-level rise is an extreme but plausible scenario by 2100. If you use the slider below and zoom in, you can see the repositories that would be affected by 6 feet of sea level rise.

A less extreme sea-level rise scenario would still have devastating consequences for many archives. The map below features Charleston, South Carolina with 3-feet of sea-level rise. The light-blue areas show how far inland sea-level rise may occur.

Even archives far from the coast will likely experience increasingly devastating disasters due to climate change. The  National Climate Assessment  projects that increasingly extreme precipitation events will lead to more flooding. The  northern Great Plains  are projected to have "an increase in the number of heavy precipitation events (events with greater than 1 inch per day) for much of the region."

The Federal Emergency Management Agency produces Flood Hazard Maps which classify areas of the United States into areas at particular risk of flooding. The map below shows Lincoln, Nebraska. Purple areas depict a 1% annual chance flood hazard area (sometimes known as a "100-year flood," though this description is falling out of favor as "100-year floods" keep occurring so frequently). The lighter purple areas depict a 0.2% annual chance flood hazard area (sometimes known as a "500-year flood").

During an active hurricane or cyclone, archivists and emergency managers can view which archives are located in the storm's cone of uncertainty. The image below is a static image of archives in the path of Hurricane Isaias as of July 31, 2020.

If you would like to try creating versions of the maps depicted above, you can access this publicly-accessible web map of the RepoData with various weather, climate, and infrastructure data layers. Click on the "Content" menu to try turning different layers on and off.

To access the RepoData data set, you can visit the GitHub repository and download data for the entire United States.

For any questions, please contact Eira Tansey